Zirconium molybdosilicate (ZrMoSi) gel prepared using 99Mo radiotracer via peroxo route was used as a base material for 99Mo/99mTc column generator. The 99mTc elution yield and 99Mo breakthrough in the eluate were studied as a function of the pH-value of gel precipitation, gel drying temperature and Zr:Mo:Si molar ratio. Precipitation pH-value of 2, drying temperature of 100 ℃ and Zr:Mo:Si molar ratio of 0.5:0.5:1 were found to be the optimum conditions achieving 99mTc elution yield of 82% and 99Mo breakthrough of 1.0E-3%. The gel prepared with the optimum conditions was characterized by BET surface area and pore size analyzer, IR spectroscopy, thermal analysis (TGA and DTA), XRD, XRF and FESEM. Technetium-99m eluted from the optimum ZrMoSi 99Mo/99mTc generator was found to have a high radiochemical purity (98% as 99mTcO4–) and chemical purity meeting criteria of clinical grade.